Numerous industrial applications exist for methods by which normally liquid substances entrained within solids are removed therefrom and recovered. For example, various methods and equipments are employed to remove oils from cereals and meals to recover the oils therefrom.
Another application is the treatment of tar sands in order to remove a liquid petroleum by-product from solid granulate entraining the by-product. Tar sand deposits are located at numerous locations around the world, and a number of deposits are located on the North American continent. These locations are primarily in the states of California, Kentucky, Oklahoma, Texas, and Utah of the United States and at various locations in Canada.
Recovery of the petroleum products embedded in such sands is, at present, a difficult and expensive proposition. At the present cost of petroleum, therefore, recovery of petroleum from these deposits is impracticable. As the cost of crude oil rises, however, the viability of extraction of by-products from tar sands will increase.
As can be seen from the two illustrations identified above, the particular products being worked in extraction processes can vary quite significantly. In the case of cereals and meals, the solid carrier is fairly homogenously granular. In the case of tar sand processing, however, because of the nature of the solid and, even more significantly, the viscosity of the liquid by-product to be recovered, the consistency of the product being worked tends to be clumpy, the size of agglomerations varying significantly. Even more importantly, however, the distribution of the petroleum product throughout the tar sand mass is not uniform, and what might prove to be sufficient processing for a portion of the mass might prove inadequate for other portions.
Because of the significant difference between the types of products that are subjected to extraction processes, the equipments appropriate for handling one product might tend to be very unsuitable for handling another. Percolation, a method wherein the solvent flows through the extractable material, might function well to remove oils from meal because of the relatively uniform granularity of the meal. With tar sands, however, percolation is difficult because of the compactness of the raw product to be processed. Nevertheless, percolation, if it can be performed, is a method of extraction which provides advantages in extracting the liquid by-product from its solid carrier.
Various devices and apparatus have been developed for processing heavy sedimentary solids having a liquid entrained therein. Because of the difficulty in handling such products, however, various problems go unsolved. For example, in view of the sludginess of the product being processed, bogging down and even complete clogging of machinery can easily occur. Various of the prior art structures incorporate numerous moving parts which are exposed to the sediment, and, consequently, clogging is facilitated.
It is to the desirable features and undesirable problems discussed above that the present invention is directed. It is an improved extractor which functions well to process heavy sedimentary, liquid-entraining solids to remove and recover the liquid by-products entrained in those solids. Although particularly useful for processing tar sand deposit materials to recover petroleum products embedded in such sands, it will be understood that the invention is designed to function equally as well in processing other heavy sedimentary solids.